1. Field of the Invention
The present invention relates to an apparatus for adjusting a jaw gap of a jaw cylinder for a folder, which adjusts a gap between a pair of folding jaws provided in a jaw cylinder in accordance with a thickness determined by a product thickness and a pagination.
2. Discussion of the Related Art
A conventional apparatus for adjusting a jaw gap of a jaw cylinder for a folder, which is disclosed by Japanese Patent Unexamined Publication No. Hei 4-223973), will be described with reference to FIGS. 3 and 4. In the figures, reference numerals 1a and 1b denote a pair of frames of the folder; 2, a folding cylinder shaft of which is rotatably supported by the frames 1a and 1b. Reference numeral 3 denotes a jaw cylinder; 4, a shaft of the jaw cylinder 3; 4a, two flanges provided in the shaft 4 which is rotatably supported by the frames 1a and 1b.
Reference numeral 5 denotes a jaw cylinder driving helical gear fitted to a left end portion of the shaft 4 of the jaw cylinder 3; 25, a folding cylinder driving helical gear fitted to a left end portion of the shaft of the folding cylinder 2. The folding cylinder driving helical gear 25 and the jaw cylinder driving helical gear 5 mesh with each other so as to be driven.
Reference numeral 6 denotes a stepped bush movably fitted to the shaft 4 of the jaw cylinder 3; 7, a gap adjusting helical gear fixed to a left end portion of the stepped bush 6; 8, an inverse gear fixed to a right end side of the stepped bush 6; 23, a helical gear meshing with the jaw cylinder driving helical gear 5; and 22, a helical gear meshing with the gap adjusting helical gear 7.
Reference numeral 14 denotes a folding jaw support movably fitted to the shaft 4 between the respective flanges 4a; 13, two gears fixed to the folding jaw support 14; and 10, other folding jaw supports whose left side support is fixed to the stepped bush 6 and whose right side support movably fitted to the shaft 4 of the jaw cylinder 3. Reference symbols a and b denote coaxial gears rotatably fitted to the respective flanges 4a; and c, gears rotatably fitted to the respective flanges 4a. The gears c mesh with the gear b and the gear 13.
Reference numeral 11' denotes levers swingably fitted to the right and left folding jaw supports 10; 11, movable jaws fixed to the levers 11' through a key 100; and 15, stationary jaws fixed to the folding jaw support 14.
Reference numeral 16 denotes a motor; 17, a threaded portion provided on an output shaft end of the motor 16; 19, a cylindrical body; and 18, a nut provided on the cylindrical body 19 in such a manner that the nut 18 is screwed to the threaded portion 17. Reference numeral 20 is a protrusion provided in an inner surface of the cylindrical body 19; and 21, a shaft attached to the frame 1a. A groove formed in the shaft 21 in the axial direction thereof engages with the protrusion 20. Reference numeral 22 denotes a helical gear rotatably supported by the cylindrical body 19; and 23, a helical gear attached to the helical gear 22.
The jaw cylinder 3 includes the above-mentioned parts 4 to 15. Reference numeral 9 denotes a jaw gap adjusting unit which is constituted by the above-mentioned parts 16 to 23, and 12 is a rotational direction reverse transmission unit which is constituted by the above-mentioned gears a to c.
The operation of the apparatus for adjusting the jaw gap of the jaw cylinder shown in FIGS. 3 and 4 will be described. When adjusting the gap between the folding jaws 11 and 15 of the jaw cylinder 3, the motor 16 of the jaw gap adjusting unit 9 is driven to make the threaded portion 17 rotate such that the nut 18, the cylindrical body 19 and the helical gear 22 are moved in the axial direction (in the direction of an arrow A) thereby to allow the gap adjusting helical gear 7 to rotate in the circumferential direction with respect to the jaw cylinder driving helical gear 5.
Also, the rotational movement of the gap adjusting helical gear 7 is transmitted to the stepped bush 6 and the right side of the folding jaw 10 so that the folding jaw 11 which is swingable by an open/close unit (refer to FIG. 1) rotates clockwise with respect to a folding blade 24 of the jaw cylinder 2 as shown in FIG. 4.
Further, the rotational movements of the gap adjusting helical gear 7 and the stepped bush 6 are transmitted to the inverse gear 8, and the rotational movement of the inverse gear 8 is then transmitted to the folding jaw support 14 through the gears a, b and c of the rotational direction reverse transmission unit 12 and the gear 13, whereby the rotational jaw 15 rotates counterclockwise with respect to the folding blade 24 as shown in FIG. 4.
With the above-mentioned operation, the gap between the folding jaws 11 and 15 of the jaw cylinder 3 is adjusted.
In the above-mentioned conventional apparatus for adjusting the jaw gap of the jaw cylinder for the folder shown in FIGS. 3 and 4, since the rotational direction reverse transmission unit 12 having a large number of parts is disposed within the jaw cylinder 3, the structure of the jaw cylinder 3 is made complicated and the costs are increased. Further, since the rotational direction reverse transmission unit 12 is disposed within the jaw cylinder 3, the width of the jaw cylinder 3 is lengthened, a gap between the frames 1a and 1b are widened, and the entire folder is made large in size to require a large installation space, resulting in such a problem that the costs are increased.